Theses and Dissertations at Montana State University (MSU)
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Item Evaluation of methanotrophic activity and growth in a methanotrophic-heterotrophic co-culture(Montana State University - Bozeman, College of Engineering, 2021) Kilic, Ayse Bengisu; Chairperson, Graduate Committee: Ellen G. Lauchnor; Erika J. Espinosa-Ortiz, Brent M. Peyton and Ellen Lauchnor were co-authors of the article, 'Methane-based bioreactor configurations in value-added product development: a review' submitted to the journal 'Journal of bioscience and bioengineering' which is contained within this thesis.; Erika J. Espinosa-Ortiz, Brent M. Peyton and Ellen Lauchnor were co-authors of the article, 'Evaluation of methanotrophic activity and growth in a methanotrophic-heterotrophic co-culture' submitted to the journal 'Engineering in life sciences' which is contained within this thesis.Methane is a potent greenhouse gas (GHG) and accounts for 20-30% of the GHG emissions globally. In nature, methane is utilized as a sole carbon and energy source by a group of bacteria referred to as methanotrophs. Methanotrophs have been reported to have the ability to form close associations with other microorganisms such as heterotrophic bacteria in the environment. Therefore, understanding methanotrophic activity and growth in a microbial consortium with heterotrophic bacteria is of interest from an environmental and biotechnology perspective. In this study, a methanotroph; Methylocystis sp. NLS7 and a heterotrophic bacterium, Pseudomonas chlororaphis, were co-cultivated in a methane-fed bioreactor with a dialysis membrane device used to separate the species physically. It was hypothesized that the co-culture would exhibit enhanced methanotrophic activity and microbial growth of NLS7 in NLS7- P. chlororaphis co-culture. The methane-oxidation rate and microbial growth rate of NLS7 were evaluated as a functional response variable to the presence of P. chlororaphis. In addition, the effects of NLS7 growth were evaluated on the growth of P. chlororaphis. Our findings indicated that the presence of P. chlororaphis does not have any beneficial effects on Methylocystis sp. NLS7 activity and growth. However, the growth of P. chlororaphis in the co-culture with solely methane as a carbon source indicated that P. chlororaphis is likely gaining carbon and energy from by-products of methane oxidation by Methylocystis sp. NLS7 since P. chlororaphis could not utilize methane as a carbon and energy source. The results of this study give us an important insight into the activity and the growth of methanotrophic consortia in methane-driven ecosystem.Item Systems analysis of engineered and natural microbial consortia(Montana State University - Bozeman, College of Engineering, 2013) Bernstein, Hans Christopher; Chairperson, Graduate Committee: Ross Carlson; Ross P. Carlson was a co-author of the article, 'Microbial consortia engineering for cellular factories: in vitro to in silico systems' in the journal 'Computational and structural biotechnology journal' which is contained within this thesis.; Ross P. Carlson was a co-author of the article, 'Design, construction and characterization methodologies for synthetic microbial consortia' in the book 'Methods in molecular biology, engineering multicellular system' which is contained within this thesis.; Steven D. Paulson and Ross P. Carlson were co-authors of the article, 'Synthetic Escherichia coli consortia engineered for syntrophy demonstrate enhanced biomass productivity' in the journal 'Journal of biotechnology' which is contained within this thesis.; Maureen Kessano, Karen Moll, Terence Smith, Robin Gerlach, Ross P. Carlson, Brent M. Peyton, Robert D. Gardner and Ronald C. Sims were co-authors of the article, 'Direct measurement and characterization of active photosynthesis zones inside biofuel producing and waste-water remediating algal biofilms' submitted to the journal 'Biotechnology and bioengineering' which is contained within this thesis.; Jacob P. Beam, Mark A. Kozubal, Ross P. Carlson and William P. Inskeep were co-authors of the article, 'In situ analysis of oxygen consumption and diffusive transport in high-temperature acidic iron-oxide microbial mats' in the journal 'Environmental Microbiology' which is contained within this thesis.; Alissa Bleem, Steven Davis and Ross P. Carlson were co-authors of the article, 'Chacterization of an artificial photoautotrophic-heterotrophic biofilm consortium composed of synechococcus PCC 7002 and Escherichia coli MG1655' which is contained within this thesis.Microorganisms are ubiquitous and typically exist within complex interacting communities or consortia. Microbial consortia are capable of cooperating in a coordinated fashion to extract mass and free energy from their environment. Chemical and biological engineers have long been keen to harness microbial processes for the development of technologies with applications ranging from energy capture to environmental remediation to human health. The pursuit of novel microbial biotechnologies has given rise to the relatively new discipline of microbial consortia engineering, which differs from and expands upon more traditional monoculture based practices. Many successful examples of applied and/or engineered microbial consortia mimic fundamental ecological strategies observed from nature, highlighting the importance for engineers to study natural biological phenomena. The overarching goal for this dissertation was to observe and quantitatively characterize interactions and physical phenomena occurring within select microbial consortial systems. The technical research presented here explores microbial consortia on three main fronts: (i) metabolically engineered heterotrophic systems, (ii) photoautotrophic-heterotrophic biofilm systems and (iii) naturally occurring thermo-acidophilic microbial mat systems. The metabolically engineered systems were designed to mimic a common ecological strategy involving syntrophic metabolite exchange via primary-productivity coupled with secondary consumption of potentially inhibitory byproducts (i.e., acetic acid). This system exhibited enhanced biomass productivity as compared to monoculture controls. The primary-productivity concept was also explored, in a more traditional sense, by characterizing production, consumption and exchanges of oxygen within photoautotrophic-heterotrophic biofilm systems. Tight spatial coupling of oxygenic-photosynthesis and aerobic-respiration was observed in both biofuel producing and waste-water remediating biofilm communities. The role of oxygen as an important terminal electron acceptor was also investigated in pristine Fe(III)-oxide microbial mats from geothermal springs located in Yellowstone National Park (USA). For these systems, oxygen availability defines ecological niche environments that spatially govern specific community member abundances and activities. Classical chemical engineering reaction and diffusion analysis was used to model concentration dependent oxygen consumption kinetics and establish that these mats are likely mass transfer limited. Both primary-productivity and microbially mediated oxygen reactions are interrelated, cross-cutting themes throughout this dissertation. The research described here is interdisciplinary chemical engineering that utilizes fundamental microbial ecology as a foundational platform.